Volvo Penta AQ series 290 water inlet casting - permanent fix

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,307
Volvo casting 854031 as used on the 290, 280, DPA, etc is a known weak link on the AQ series drives

try as I might, I never had one last more than 3 years and that is even with epoxy coating the new ones.

they just dissolve in brine and last about 5 years in fresh water.

so I think I found a permanent fix for mine





The old one has 40 hours of run time or about 15 months and was pulled last January when I pulled the motor. you can see the pitting starting in a bunch of locations and the casting has a bunch of oxidation blisters under the remaining paint. the epoxy paint was POR15 with the POR15 hardnose paint.

the new one is 316L stainless, laser cut, tig welded and tonight I will hit the interior edges with the die grinder and clean up the exterior.

something else may corrode on the drive now, however this wont be it.

would have machined a billet unit, however the laser and tig were much faster.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,307
Not really. The rubber gasket will isolate it. However the stainless H frame is already a large piece of stainless attached to the outdrive.
 

PatinIdaho

Chief Petty Officer
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Oct 7, 2014
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405
Nice work!. Bet you could almost make a living off making and selling them or at least some extra boat bucks. You have the hard part done.
 

HorizonblueDK

Petty Officer 1st Class
Joined
May 27, 2010
Messages
355
There is still an electrical connection through the screws, so galvanic corrosion can occur. But yes, there is a huge stainless steel bracket for the hydraulic rams on this outdrive, so this inlet won't be the only stainless part. I believe I have seen this inlet, new from Volvo, in plastic, instead of aluminium ?!. I suspect that some of the reason for the corrosion, is that there is a weak connection between the inlet and the rest of the outdrive, because of the rubber gasket. The aluminium inlet is painted, and therefor hardly any connection through the screws.
 
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